There are still many unanswered questions surrounding the resignation of CIA Director David Petraeus over an alleged extra-marital affair.

New details suggest a friend of Petraeus' family sparked the FBI investigation that revealed the affair and lead to his stepping down last Friday.

But congressional leaders say there are even more pressing questions in this case, like what the White House knew and when.

Is the timing of Petraeus's resignation connected to his scheduled testimony on the Consulate attack in Benghazi? CBN News Terrorism Analyst Erick Stakelbeck has more, following Jennifer Wishon's report.

"We received no advanced notice. It was like a lightning bolt," California Sen. Dianne Feinstein, D-Calif., head of the Senate Intelligence Committee, said.

Lawmakers are also skeptical of the timing of Petraeus' resignation, which came just as the CIA director was scheduled to testify about the Sept. 11 attack on the U.S. Consulate in Benghazi, Libya.

"It seems this [the investigation] has been going on for several months and yet now it appears they're saying the FBI didn't realize until Election Day that General Petraeus was involved. It just doesn't add up," Rep. Peter King, chairman of the House Homeland Security Committee, said.

"At the end of the day, the one thing that has to happen, in my view, is we've got to get to the bottom of Benghazi," Sen. Lindsey Graham, R-S.C., told CBS's "Face the Nation."

"I don't see how in the world you can find out what happened in Benghazi before, during, and after the attack if General Petraeus doesn't testify," he said.

Friends said the alleged affair began a week before Petraeus became CIA director and ended four months ago.